Lets take that given, i.e. massive IO works reliably only when a single process has access.
How will SQLite handle concurrent access by multiple processes when git/npm/whoever switches over to it?
(A: It doesn't, even in a single process, you need to obtain a global lock to write while all readers pause.)
Readers don't have to pause.
But, the original post sort of handwaves about what pathological filesystem use is.
The examples they chose (git & npm) imply # of files.
I posit that as easy as it was to handwave that SQLite is obviously superior for npm/git than using N files, it'll be equally easy to handwave that it won't be a problem because SQLite is one file instead of many.
Sqlite lives inside a single file. I've never heard of any corruption issues in practice, even with thousands of high-throughput reads and writes -- the kinds that are being complained about. Because this is something SQLite is really good at.